SEMIRIGID
There is the question of the TACAN, which the crew would probably have relied upon rather than TANS, to get to the close in turning point had they got a useable reading. But no one seems to want to contemplate this.
The TACAN CU was set accordingly and this crew had grave misgivings about the accuracy of TANS.
Other crews who have done this run could clear this up as to what was the usual practice but seem somewhat shy about disclosing it.
The accident is wholly explained by simply running on too far by reference to a false reading on the TACAN when ground detail was obscured by the ground hugging mist.
Those who look for control faults must realise that the aircraft appears to have been in control for at least the last 5 seconds as the final evasive manouevre needed that much time to get them from the extended straight and level bit (Boeing simulation, etc) - this leaves a narrow window of slightly more than 10s for a control fault to have had effect and then clear while the pilots did nothing when the greatest danger was to carry straight on towards the high ground that they knew was there and that they were preparing to turn away from at close range AT ANY SECOND (this WAS their intended path) - no engine hiccup should have distracted them from that.
Of course, had the TACAN been used its nature is that it is accurate - unless the ground side was tampered with to give a false reading (which is ridiculously easy to do in practice). BUT this would have been sabotage and therefore the authorities immediately ruled it out ...????